Lysine is frequently a first- or second-limiting amino acid in poultry diets. Improving the efficiency of lysine use for protein synthesis would effectively lower the lysine requirement and decrease feed costs. Understanding how lysine is degraded and how the degradation is regulated would identify potential molecular targets for interventions to decrease lysine degradation. To better understan...

Three levels of lysine (90, 100 and 110% of Ross requirement) and of pyridoxine (3, 6 and 9 mg kg(-1)) were used in a 3 × 3 factorial experiment to investigate the growth and blood antioxidant ability of broilers under high ambient temperature. None of the dietary supplements affected the weight gain during the starter and grower periods. Although no significant differences were detected betwee...

Experimentation was conducted to estimate dietary lysine needed to optimize production of summer-reared broilers between 42 to 56 d of age. Male Ross x Ross 308 chicks were placed in floor pens of an open-sided house and provided common feeds from placement to 42 d of age. During the subsequent 42 to 56 d, birds received a corn-soybean meal basal diet (18% CP and 3,250 kcal/kg ME) established t...

To investigate whether splanchnic uptake of the indicator amino acid ([1-(13)C] phenylalanine) during the fed state alters the estimate of lysine requirement, five healthy men were studied at graded levels of lysine intake, with either an oral or intravenous (IV) tracer protocol, in a randomized, crossover design. Splanchnic extraction of the oral tracer was expressed as the difference between ...

Two experiments were conducted to determine the lysine requirement of straight-run broiler chickens (Hubbard× Hubbard) during the period 4-21 (Exp. 1) and 21-40 (Exp. 2) days of age. Experiments were conducted during the summer months (June-August) in open-sided houses, thus exposing chicks to chronic heat stress. Daily min-max temperature averaged 28-40°C (Exp. 1) and 23-36°C (Exp. 2). Lysine ...

A dose-response experiment with five lysine levels (0.65, 0.80, 0.95, 1.10, and 1.25%) was conducted to evaluate the lysine requirement of male White Pekin ducklings from 7 to 21 days of age. Two hundred and eighty, 7-day-old, male White Pekin ducklings were allocated to 5 experimental treatments, each containing 8 replicate pens with 7 birds per pen. Feed and water were provided ad libitum fro...